Genotypes of erythrovirus B19, their geographical distribution & circulation in cases with various clinical manifestations

Erythrovirus B19 (B19V) is one of the erythroviruses known to be pathogenic in humans. B19V is classified into three distinct genotypes; 1, 2 and 3, differing from each other by 2-13 per cent. Genotype 1 consists of the prototype B19V isolates, genotype 2 comprises the A6, LaLi and their related isolates while genotype 3 includes the V9- and V9-related isolates. The classification of genotype 1 into two subtypes (1A and 1B) and genotype 3 into two subtypes (3a and 3b) with an estimated nucleotide difference of about 5 per cent has been done. Predominance of genotype 1 across all the continents is seen followed by genotypes 2 and 3. There are no disease-specific genotypes. All the three genotypes have been found in symptomatic as well as asymptomatic individuals and have been reported from several countries across the world. The prevalence of genotype 2 in older populations and its absence from current circulation in Northern Europe has also been reported. The present review focuses on geographic distribution and association of genotypes of B19V with different clinical manifestations.

Genotype 1 of human parvovirus B19 in clinical cases / Genótipo 1 do parvovírus humano em casos clínicos

Summary Introduction: Virus surveillance strategies and genetic characterization of human parvovirus B19 (B19V) are important tools for regional and global control of viral outbreak. In São Paulo, Brazil, we performed a study of B19V by monitoring the spread of this virus, which is an infectious agent and could be mistakenly reported as a rash and other types of infection. Method: Serum samples were subjected to enzyme immunoassay, real time polymerase chain reaction, and sequencing. Results: From the 462 patients with suspected cases of exanthematic infections, the results of the 164 serum samples were positive for B19V immunoglobulin M. Among these cases, there were 38 patients with erythema infections and B19-associated with other infections such as encephalitis, hydrops fetalis, chronic anemia, hematological malignancies. These samples were sequenced and identified as genotype 1. Conclusion: This study showed patients with infections caused by B19V and sequencing genotype 1. Continuous monitoring is necessary to detect all known genotypes, and the emergence of new genotypes of these viruses for case management in public health control activities.

Resumo Introdução: Estratégias de vigilância para o parvovírus humano B19 e caracterização genética são ferramentas importantes para o controle regional e global do surto viral. Em São Paulo, Brasil, foi realizado um estudo de parvovírus B19, monitorando a disseminação desse vírus, que é um agente infeccioso e poderia ser erroneamente relatado como uma erupção cutânea e outros tipos de infecções. Método: As amostras de soro foram submetidas ao ensaio imunoenzimático, PCR quantitativo em tempo real e sequenciamento. Resultados: Dos 462 pacientes com casos suspeitos de infecções exantemáticas, os resultados das 164 amostras de soro foram positivos para parvovírus B19 imunoglobulina M. Entre eles, 38 pacientes com eritema infeccioso apresentaram B19 associado com outras infecções, como encefalite, hidropisia fetal, anemia crônica, doenças hematológicas malignas. Essas amostras foram sequenciadas e identificadas como genótipo 1. Conclusão: Os pacientes foram infectados com parvovírus B19 e apresentaram genótipo 1. Monitoração contínua é necessária para detectar todos os genótipos conhecidos e o surgimento de novos genótipos para o controle de casos em saúde pública.

Molecular diversity of human parvovirus B19 during two outbreaks of erythema infectiosum in Brazil

Abstract This study was conducted to provide information on the genetic diversity of human parvovirus B19 (B19V) circulating in the municipality of Niterói, Rio de Janeiro, Southeast Brazil during 1996-2006, a period with two distinct outbreaks of B19V infection: 1999-2000 and 2004-2005. A total of 27 sera from patients with erythema infectiosum and five sera from HIV-infected patients that tested positive for B19V DNA during the study period were analyzed. To genotype B19V strains, a semi-nested PCR for partial amplification of the capsid gene was performed and sequence analysis revealed that 31 sequences belonged to subgenotype 1a (G1a) of the main genotype 1 and one sequence was characterized as subgenotype 3b (G3b). The phylogenetic tree supported the division of the G1a into two well-defined clades with 1.3% of divergence. The low diversity of the G1a strains may be explained by the fact that all patients had acute B19V infection and 30/32 sera were collected during two distinct outbreaks. The G3b strain was from an HIV-infected patient who seroconverted to anti-B19 IgG antibodies in September/2005. This is the first report of G3b in the state of Rio de Janeiro.